1. Field of the Invention
The present invention relates to hydraulic compression tools and, more particularly, to a hydraulic compression tool having a rapid ram advance.
2. Prior Art
U.S. Pat. No. 5,979,215 discloses a hand operated hydraulic compression tool with a rapid ram advance. A mechanical actuator pushes against a rear end of the ram to move the ram at a first rate of movement until a predetermined resistance is encountered by the ram. After resistance is encountered, the hydraulic fluid pump moves the ram at a slower second rate of movement. One disadvantage of the tool is that it is relatively large. Battery operated hydraulic compression tools are known in the art, but they do not comprise a rapid ram advance.
U.S. Pat. No. 5,727,417 discloses a portable battery powered crimper. The crimper has a hydraulic pump with a rotating wobble plate connected to an electric motor. The wobble plate axially rotates to reciprocate hydraulic pistons. However, the crimper does not comprise a rapid ram advance.
There is a desire to provide a battery operated hydraulic crimping tool which has a rapid ram advancement system to increase the speed for crimping an electrical connector onto a conductor and for allowing a rechargeable battery to perform more crimping operations before having to be recharged. There is also a desire to provide a battery operated hydraulic crimping tool which can use a relatively low volume per revolution revolving hydraulic pump (to minimize cost, weight and size), but which can nonetheless maximize crimp speed.
In accordance with one aspect of the present invention, a battery operated hydraulic compression tool is provided comprising a frame; a hydraulic fluid reservoir connected to the frame; an electric motor driven hydraulic pump connected to the hydraulic fluid reservoir; a ram movably connected to the frame; and a multi-speed ram advancement system for advancing the ram in at least two different rates of movement on the frame. The advancement system comprises a rapid advance actuator located directly against the ram, a suction conduit located between the hydraulic fluid reservoir and an area of the frame holding the ram; and a hydraulic bypass system located between the pump and the ram for conduiting hydraulic fluid past the rapid advance actuator to the area of the frame holding the ram.
In accordance with another aspect of the present invention, a battery operated hydraulic compression tool is provided comprising a frame; a hydraulic fluid reservoir connected to the frame; an electric motor driven hydraulic pump connected to the hydraulic fluid reservoir; a ram movably connected to the frame; a hydraulic fluid conduit system in the frame between the pump and the ram; and a mechanical actuator provided in the conduit system for contacting and pushing against the rear end of the ram. The conduit system is adapted to conduit hydraulic fluid from the pump against both the rear end of the ram and a rear end of the mechanical actuator.
In accordance with one method of the present invention, a method of advancing a ram in a hydraulic compression tool is provided comprising steps of actuating an electric motor in the tool to actuate a hydraulic pump of the tool to move the ram relative to a frame of the tool at a first rate of movement comprising hydraulic fluid pushing against a first pushing surface connected to the ram to push the ram forward; and automatically switching movement of the ram to a second slower rate of movement when the ram encounters a predetermined resistance to forward movement on the frame, wherein the step of automatically switching comprises a bypass valve in the tool opening to allow hydraulic fluid to be pumped by the pump into an area adjacent a rear end of the ram.